MADISON, Wisconsin (CNN) -- Exit polls from the Wisconsin governor's recall election indicate a tight race that's too early to call and may be undecided until the last votes are counted.

Votes were just beginning to trickle in but exit polls showed Gov. Scott Walker, a Republican hero for pushing austerity measures that stripped collective bargaining rights from most public unions, leading Milwaukee Mayor Tom Barrett, his 2010 opponent, by a 52-48 margin.

Public opinion polls leading up to the vote have shown Walker holding a narrowing lead and exit polls suggest the race will be tight, with 35% of those responding identifying themselves as Democrats, 33% saying they're Republicans and 32% saying they're independents.

A state official said on condition of not being identified that turnout appeared to be strong, with reports of some polling places running out of forms for same-day voter registration.

Both Walker and Barrett cast their ballots Tuesday morning in an election expected to hinge on which side does a better job of motivating its supporters to vote.

Exit polls indicated that both sides had succeeded in those efforts, with two key groups voting above 2010 levels -- 23% of those voting said they were 65 or older, voters who tend to be more Republican, and 32% said either they or someone in their household is a union member, who are usually more Democrat.

The vitriolic campaign has included tens of millions of dollars in funding from outside the state, mostly for the Republican governor.

"We can't spike the ball on the 10-yard line," Walker said Monday night in a Green Bay restaurant, within walking distance of the Packers' famed Lambeau Field. "We've got to take it all the way into the end zone."

The race is a rematch of the 2010 governor's contest, won by Walker with more than 52% of the vote. A victory by the first-term governor could give Republicans a major boost in efforts to make Wisconsin a battleground state in the November presidential election.

President Barack Obama easily won the state in 2008, but Walker's unyielding commitment to fiscal austerity in the face of chaotic protests last year made him the poster child for tea party conservatism. If Walker loses, he will be only the third governor in U.S. history ousted by a recall election.

Along with the gubernatorial recall, voters will decide whether Walker's lieutenant governor and four Republican state senators keep their jobs. Just one GOP loss among the four state senators facing recall races would flip control of the chamber back to Democrats, at least until the next election in November.

A former Republican state senator ousted in a Wisconsin recall vote last year said Tuesday that the political wound he suffered was worth it because of the fiscal austerity achieved.

"I lost my job standing for something, and I was standing for the people, fiscal responsibility and the future of this country and the state and its residents," Dan Kapanke said, adding that "the times dictate tough decisions, and we want our elected officials to do the right thing and worry about the future and not just about the next election."

Walker complains that repeated recall efforts over past years are stalling progress and costing the state needed money.

On Tuesday, Barrett said he agrees that voters are tired of recall politics, but he blamed Walker for creating a divisive political environment that inspired the effort to oust him.

"What Gov. Walker doesn't say is he was the one who, these are his words, dropped the bomb and attempted to divide and conquer. So he set out on a strategy to divide this state. He succeeded in dividing the state," Barrett said, adding that the proper course now is to "get rid of the instigator rather than to allow him to continue because I think this state will remain this bitterly divided if he continues in office."

About $64 million has been spent on the race since November, an analysis from the Center for Public Integrity found. That's a state record, shattering the record of $37.4 million spent during the 2010 governor's race.

Walker outraised his opponent by an almost 8-1 ratio, collecting $30.5 million to Barrett's $4 million. Roughly two-thirds of Walker's contributions came from out of state, the Center for Public Integrity reported, while only a quarter of Barrett's funds originated from outside Wisconsin. Barrett said Tuesday that such outside influence is a change for Wisconsin.

"What's happened is, Scott Walker has become the rock star of the far right and has been able to raise literally millions of dollars from out-of-state contributors," Barrett said.

The recall effort was spurred by a Walker-backed law, signed in March 2011, to limit the collective bargaining rights of state worker unions.

During a bitter fight over the law last year, Democratic legislators left the capital to prevent a quorum, and tens of thousands of protesters converged on the State Capitol building in what became an occupation.

After the law was signed, Democrats immediately began a recall effort that led to Tuesday's vote.

Walker has defended his budget actions as necessary for the fiscal health of his state and described his campaign as one of a strong leader who is making the necessary "tough decisions."

The campaign has been fierce, with campaigners complaining of keyed cars, verbal harassment and a general lack of tolerance for differing opinions.

"We have an example of Hatfields and McCoys going on in this state like we have never seen," said Brian Nemoir, a Milwaukee-based Republican strategist. "People are hyper-engaged, as much in support for their own candidate as in disgust for the opponent."

Handmade signs are nearly as prevalent as official ones. Some locals say they have resorted to lowering their voices in public when discussing the recall to avoid setting off arguments with strangers.

A litany of Republican stars have campaigned for Walker, including fellow governors Chris Christie of New Jersey, Nikki Haley of South Carolina, Bobby Jindal of Louisiana and Bob McDonnell of Virginia, as well as U.S. Sen. Marco Rubio from Florida.

Americans for Prosperity, a conservative advocacy group built around many of the same principles as the tea party, has pumped more than $10 million into Wisconsin backing Walker's policies.

Barrett, meanwhile, got his own high-powered support from former President Clinton, as well as Democratic National Committee Chairwoman Debbie Wasserman Schultz and Maryland Gov. Martin O'Malley.

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